﻿//------------------------------------------------------------------------------------------------------
// <summary>
//     The following code is allowed to be used inernally in Pfizer China only, 
//     you are not permitted neither to use the contents nor disclose it in any
//     manner to third parties.
// </summary>
// <copyright file="ValidateCodeHelper.aspx.cs" company="Pfizer China">
//     Copyright (c) Pfizer China. All rights reserved.
// </copyright>
//------------------------------------------------------------------------------------------------------
using System;
using System.Drawing;

namespace DutyWeb.Login
{
    public partial class ValidateCodeHelper : BasePage
    {
        /// <summary>
        /// Page load
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        protected void Page_Load(object sender, EventArgs e)
        {
            this.CreateCheckCodeImage(this.RndNum(5));
        }

        /// <summary>
        /// Make random
        /// </summary>
        /// <param name="length"></param>
        /// <returns></returns>
        private string RndNum(int length)
        {
            int number;
            char code;
            string checkCode = String.Empty;

            System.Random random = new Random();

            for (int i = 0; i < length; i++)
            {
                number = random.Next();
                if (number % 2 == 0)
                {
                    code = (char)('0' + (char)(number % 10));
                }
                else
                {
                    code = (char)('A' + (char)(number % 26));
                }

                checkCode += code.ToString();
            }

            /// Response.Cookies.Add(new HttpCookie("yzmcode", checkCode));
            CheckCode = checkCode;

            return checkCode;
        }

        /// <summary>
        /// Create check code image
        /// </summary>
        /// <param name="checkCode"></param>
        private void CreateCheckCodeImage(string checkCode)
        {
            if (checkCode == null || checkCode.Trim() == String.Empty)
            {
                return;
            }

            System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 12.5)), 22);
            Graphics g = Graphics.FromImage(image);

            try
            {
                ///make random
                Random random = new Random();
                ///clear picture 
                g.Clear(Color.White);

                for (int i = 0; i < 25; i++)
                {
                    int x1 = random.Next(image.Width);
                    int x2 = random.Next(image.Width);
                    int y1 = random.Next(image.Height);
                    int y2 = random.Next(image.Height);
                    g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);
                }

                Font font = new System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));
                System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true);
                g.DrawString(checkCode, font, brush, 2, 2);

                ///draw picture 
                for (int i = 0; i < 100; i++)
                {
                    int x = random.Next(image.Width);
                    int y = random.Next(image.Height);
                    image.SetPixel(x, y, Color.FromArgb(random.Next()));
                }

                ///draw picture
                g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
                System.IO.MemoryStream ms = new System.IO.MemoryStream();
                image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
                Response.ClearContent();
                Response.ContentType = "image/Gif";
                Response.BinaryWrite(ms.ToArray());
            }
            finally
            {
                g.Dispose();
                image.Dispose();
            }
        }
    }
}

